Water heater



FIG. 1 is a front perspective view of a water heater showing the new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a left-side elevation view thereof;

FIG. 6 is a right-side elevation view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines represent portions of the water heater that form no part of the claimed design. 

CLAIM We claim the ornamental design for a water heater, as shown and described. 